Narrow is used in the contexts of narrow roads or streets or a narrow-minded person. I guess narrow is used more figuratively and thin is used in physical contexts (thin body type, thin hair, thin atmosphere)
slim
Sally is as thin as a reed, exactly as a model should be.
Thin is an adjective.If you need a synonym for thin, you can use skinny, svelte, slender, willowy, slight; or narrow, depending on the usage.
just one
One possibility is notch.
trench fosse
A thin rubber felxible bag, narrow at one end. Blown up with air or helium. Typically used at parties and festivals.
"Thin" can be made into the one-syllable word "thing" by adding the letter "g."
No. Within is one word, pronounced wi-thin.
Acicular is the word applied to crystals that are long and thin; asbestos is one material that has a very high ration of length to width.
The word cot meaning a narrow bed, especially one made of canvas on a collapsible frame, is a British word. The word is actually Hindi (India) for contrivance.
One word that fits this definition is broth.